AVS 54th International Symposium
    Advanced Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM5
Periodic Nanostructures by Glancing Angle Deposition

Tuesday, October 16, 2007, 9:20 am, Room 617

Session: Glancing Angle Deposition
Presenter: C.M. Zhou, Rensselaer Polytechnic Institute
Authors: C.M. Zhou, Rensselaer Polytechnic Institute
D. Gall, Rensselaer Polytechnic Institute
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Periodic Ta nanopillar arrays were grown by glancing angle deposition onto patterned substrates. Both the effects of pattern size and surface diffusion on morphological evolution were studied by varying the pattern length-scale and by growing at temperatures Ts ranging form 200 to 900 oC. The surface patterning experiments show a direct scaling, indicating that the overall nanopillar morphologies are determined by geometric shadowing and are for Ts = 20 oC independent of material parameters such as the characteristic length-scale for surface diffusion. However, at high growth temperatures, the increased adatom diffusion length causes Ta nanopillars to grow in a competitive growth mode, which in turn results in the breakdown of the regular array morphology. Glancing angle deposition has also been extended to fabricate novel Ta/Si two component nanostructures onto self-assembled close-packed silica nanosphere arrays. The two component nanostructures are shaped into zigzags or nanopillars by adjusting the deposition angle and/or the substrate rotation. By manipulating the sequence of the deposition, that is, by sequential or simultaneous deposition from two sources, complex nanostructures are formed where the two components are stacked vertically, laterally, or in a checker board arrangement. Scanning electron microscopy, back scattered imaging, and transmission electron microscopy provide clear compositional and microstructural contrast and show sharp vertical and horizontal interfaces.